Residences and small businesses often have the need for an inexpensive intercom system. Conventional intercom systems are usually either built into a residence at great expense, or they are added later and must be wired in. These systems are confusing to use and add clutter and confusion to a house. Add on intercom systems tend to be unsightly, and wiring is difficult at best.
Sophisticated residential phone systems which have intercoms built in are available. These systems are expensive and require that special wiring be installed so that calls can be directed to specific phones. It is also possible that specially equipped telephones can be made to ring individually over existing house wiring. Basically, these systems are the equivalent of those used in small businesses. No system now exists whereby a user can readily adapt existing low cost telephone extensions and wiring to make intercom calls within the residence or small business.